Power-transmission mechanism



June 6, 1939. A. H. JESSEN 2,161,473

POWER-TRANSMIS S ION MECHANI SM Filed March 15, 1937 2 Sheets-Sheet 1 Vx \w nvvtnrok ARNOLD H. JESSEN IITIPRNEY June 6, 1939. A. JES SEN2,161,473

POWER-TRANSMISSION MECHANISM Filed Marcfi 15, 1957 2 Sheets-Sheet 2 6'4-5 an an i Iii/70- 1 16.12. FIG. 15.

INVENTOR 47c ARNOLD H. JESSE/V Y M d 7M F'IG. I6. ATTORNEY Patented June6, 1939 UNITED STATES 2,161,473 POWER-TRANSMISSION MECHANISM Anion h.Jessen, Los iine'eles, cant. Appliba t idn Marc-11 1's, 1937. Serial No.130, 83!

11 Claims. (01.19248) This invention relates to 'overruning'c'lutches ofthe type which is disclosed in my Pate'nt No. 2,065,938, "December29,1936, and it has for its object the adaptation of clutches of thattype to 5 wider fields of utilization. As "shown; it is applied totransmission gearing, it being particularly adapted for thechanging ofspeeds of automotive vehicles, although it is capable of more generaluse. In Fig. '11 of my said .pate'ntI have shown in how the 'overrunningclutch is applied to one of the pinions of the transmission"garin'g. Butsuch gearing usually provide for three speeds in the forward "directionand one speedffor the reverse. By my present invention. all of these 15several speeds 'inay be obtained by the simple manipulation of a singleshifting lever.

In the accompanyingd'rawings and in the following specification I havedescribed estrus-tare which em'b'odies my preferred form "of the inven-20 -=ti'n. However, it 'is realized that details di's closed may bemodifiedfwithoiit departure from.

the principles of the invntionand I 'desire "it to be understood thatthe claims hereof are not intended to be limited to such detailsianyfarther 25 than their express terms require.

In the drawings, Fig. l isa central longitudinal section through thetransmission casing showing, partly in elevation, the various gears andthe clutch-control mechanism; Fig..=2 is an enlarged 30 View of certainof the parts shown in Fig. 1; Fig. 3 is -a cross-section on the line3--3 of Fig. 2; Fig. 4 is a plan view of the roller cages with therollers therein, one of the shifting-collar lugs he:

3 ing-shown in section; Fig-5 is a cross section on the line 5-5 o'f'Fig. 2; Fig. 6 is a view partly in section, of a detail 'ofthe shiftingmechanism; Fig. 7 is a section on line ;l! of Fig/6 is a View like Fig.'7 with some 'of .the parts ma shifted 40 position; and Figs. :9 to 13are diagrammatic views of the parts shown in the center of Fig. '4

with the shiiting collar lug in its several. positions; Fig. 14 is afragmentary view similar to Fig. 5 but showing a modifie'dstructure;Figs. 15

45 and 16 show a modification of the slotted hubs and the lugs whichcooperate with them.

Looking first at Fig. 1, 2-0 represents,in-section,

the casing for the transmission "gearing. At the left of this casing isshown-the adjacent end of 50 the driving -in'ernbe'r 21 which maybe therear end of the-cran'k-shaft of an engine, the armature shaft of amotor--01 any other power-driven member. This member extends into thecasing and is rotatably mounted on roller bearings 22, :bemg

551 held against longitudinal movement by a boss 23 which surrounds themember adjacent its end and is secured to the easing any {suitable man'-ner. The inner en'd of the in'eniber 21 is enlarged and :is hollowed outto receive the end of a driven member 24 which extends through theeasing and 5 is join-na led in roller bearings at as and n, the bearings7 25 being within the enlarge'l part o'f the driving member 21, as b'estseen in Fig. 2. Near its inner end this driving rn'e'nibe'r isfurthrenla'rged 'i nto a spur gear 21; and, -'at its extreme inner :endit is iprcividedw'v ith ilffti idl thlthengaging, annular surface 28,against which clu't'ch rollers =29- are adapted to roll. That part ofthe member 2 while-h cb'i-i tain's the =cliitch- 'e'ngaging surface asis designated so and it is so 15 shown in :Fig. 5. will more clearlyappear hereinafter, the rollers -29 are adapted 'to clutch the drivingand the d r'ive'n member together so that they tui' nas a iihit.

Near the middle of the casing -20, the driven 20 member or shaft 2!earrieis a ball or roller bearing 3| upon which a spur gear $2 isadapted to rail freely when permitted to do so. "gear is an an'hllflusand the shaft 24 extends through it. Its hers is larger tnanftne snarewithin it to provide a space {for clutch renews 33. The interiorsurface, "28 015 the-gear is perfectly "smooth and is cdaifiial theShaft.

Mei-antes teturn iipon roc l'or shaft 34, which is secured at its endswithin the casing 20 and. is cit-ended parallel with the driven member24, is a series oftransmiss'ien gears 35, at, 31 and '38. These gearsare all connected -rigidly together, being preferably in a single piece.They vary progressively in diameter as shown. The gear 35 is meshed withthe gear 21 of the driving memher, while the gear 36 meshes with thegear 32. Thegear-B I is adapted for meshing with a gear 39 which ismounted-011a splined or fluted portion of the driven shaft 24 and isadapted to be moved to the left, as shown in 1, into mesh with the-gear-3-1 for slow-speed forward or to the right intomesh with an idler, notshown, which meshes. with the gear 38, for reverse motion. These gears-31, 38, -39 and the means for shifting the gear-39 for-m'no of mypresent invention and further "description and illustration of them aredeemed "unnecessary.

The clutch rollers 29 and '33 are plain cylinders. the axes fof whichare parallel with the-axl's'or the. driven member =25. Those parw of thesaidrii'm- V ber with whioh the rollers contact "are each provided'witha series of V'-shape'd grooves ,one for each of the rollers, withinwhich the rollers are partially housed, as shown in Fig. 5. Each rollercontacts with the inner surface 28 or 28 of the driving member 2| or thegear 32, extends across the space between the driven member 24 and thesaid driving member or gear and into its respective groove 43. When itis centered within its groove it can turn freely; but when there is arelative circumferential movement between it and the member 24,' it iscammed outwardly by one or the other of the inclined sides of the grooveand becomes jammed between it and the outer surface 28 and thus clutchesthe member 24 and said surface together.

The clutch rollers 29 lie between what may be termed fingers 4| of aroller cage which comprises the said fingers, a central circumferentialweb 42 and a hub 43 which fits about the member 24, as best seen in Fig.3. As will be shown, this cage is adapted to be locked to the saidmember to prevent relative rotative movement between them or to bereleased from locked engagement and permitted to rotate slightly on themember. When locked, the rollers are held in their central positions andare free to turn on their axes; but when the cage is released it isturned slightly on the shaft 24 and the rollers become jammed, as hasbeen stated. To make certain that the cage will turn when released,means are provided for creating a frictional drag between the surface 28and the cage. This means comprises a series of friction shoes 44, therebeing one of these shoes mounted in each of the fingers 4| of the rollercage so as to be capable of radial movement with respect to the axis ofthe shaft 24, said shoes being pressed outwardly into engagement withthe surface 28 by any suitable form of springs 45 behind them. Butlittle friction is required to effect this turning or shifting movementof the cage, and the springs 45 are made as light or weak as ispracticable.

Another cage, almost identically like the one described, is provided forthe rollers 33, and its parts are designated M 42*, 43 and 44 tocorrespond to: the similar parts of the first cage. The two cages areturned in opposite directions with their hubs abutting, as shown in Fig.4. That part of the driven member 24 that is covered by the hubs of thecages is provided with a pair of oppositely-disposed slots 46 into whichproject lugs 41 on a collar 48, the latter being provided with acircumferential groove 49 to receive a shifting yoke 50. This yokeprojects from a member 5| which is attached toa rod 52 that is mountedto slide endwise within the casing 20, this movement being imparted toit by the shifting lever 53 which is mounted for a limited universalmovement in an extension 2|! of the casing. This part of the structureis conventional and requires no further description and illustration. Aswill be understood, when the upper end of the lever 53 is moved to theleft, as viewed in Fig. 1, the collar 48 is moved to the right and whenthe lever is moved in the opposite direction the collar is moved to theleft.

The hubs 43 and 43 of the roller cages are each provided with a pair ofdiametrically-opposite slots, those in the hub 43 being designated 54and those in the hub 43* being designated 54 When the shifting collar isin its central or neutral position, the lugs 41 thereon extend throughboth of the slots 54 and 54, as indicated in Fig. 11. When the said lugsare shifted to the left into their extreme positions, as in Fig. 9, thelugs pass through the slots 54 only, and when they are shifted in, theopposite direction to the posiclutch members.

tion of Fig. 13, they pass through the slots 54 only. The open end ofone slot is in alinement with the open end of the other slot and thelugs can be shifted freely back and forth. Throughout the greater partof their depth the slots are just wide enough to accommodate the lugs.This part of the slots will be referred to as their narrow part. Whenthe lugs 41 are in these narrow parts the hubs are locked non-rotativelyto the driven member 24 and the rollers are maintained in their centralpositions in the grooves 40. Consequently the rollers do not thenfunction as For a short distance in from their open ends the slots arewidened, as shown at 55 and 55. When the collar 48 is moved to anintermediate position between its central or neutral and its extremeleft-hand position, the lugs 41 are partly within the narrow parts ofthe slots 54, thus locking the hub 43 in its neutral position, andpartly within the wide parts of the slots 54, as shown in Fig. 10. Thiswide part of the slots permits the slight relative rotative move ment ofthe hub 43 on the shaft 24 and allows the rollers 33 to roll up theinclined side of the grooves 40 into clutching position. Similarly, whenthe collar 48 is moved to an intermediate position in the oppositedirection, as indicated in Fig. 12, the hub 43 is locked to the shaft 24while the hub 43 is capable of the slight rotative movement necessaryfor causing the clutching rollers 29 to jam.

Having described my preferred structure, I will now set forth itsoperation insofar as the gears 21, 32, 35 and 36 are concerned. When theparts are in the position shown in Figs. 1 and 2, the clutch rollers 29and 33 are all in their neutral positions, as in Fig. 5. That is becausethe lugs 41 extend into the narrow parts of the slots 54 and 54 and thehubs of both roller cages are held from rotation on the driven member24. If the driving member 2| be rotating, the gear 21 is also rotating,driving the gear 32 through the gears 35 and 36. But the driven member24 is not turned. If, now, the shifting lever 53 be drawn back to shiftthe lugs 41 to their intermediate position, as in Fig. 10, the clutchrollers 29 are still held in their non-operative positions, because thelugs 41 are in the narrow part of the slots 54. At the same time,however, the hub 43 is permitted to rotate slightly under the influenceof the drag shoes 44 of the gear 32, with the result that the clutchrollers 33 are carried up the inclined sides of the grooves 40 and arejammed between those sides and the surface 28 of the said gear 32. Thatgear is thus clutched to the driven shaft 24 and the latter is rotatedat the intermediate speed. In the direction of the applied torque, thespeed of the shaft must be at least as great as that of the gear. Butits speed can exceed that of the gear; for if the gear be turning moreslowly, the backward drag of the shoes 44 will simply move the rollers33 back to their central or non-operative position. They cannot be movedfarther than that because the straight side of the slots 54 will engagethe lugs 41 when that position is reached. It will be seen, therefore,that when the parts are positioned as indicated in Fig. 10, the clutchlocks in one direction only; and if the structure be employed in anautomotive Vehicle, there is free wheeling in the forward direction.That is. what maybe termed the single lock set-up.

If, now, the lugs 41 be shifted in the same direction to the end of theslots 54, as in Fig. 9, the hub 43 is free to shift in either direction,

being entirely :free from the lugs. Consequently, the rollers 33 willclutch on either side of the-V- shaped grooves. This is the double lockset up. The :driven member 24 is clutched to the gear 32 so that therecan be no relative movement bee tween them more than is necessary forshifting the rollers from one inclined side of the grooves to the other.No free wheeling is possible with this set-up.

Whenthe'lugs 41 are shifted into the position indicated in Fig. 12, thehub 43 may turn su'fii ciently to allow the rollers 29 to clutch thedriving and driven members together and the two will turn as a unit athigh speed. At the same time, the hub 43 will be held by the engagementof the lugs within the narrow part of the slots 54 and the rollers 33will be non-operative. But the driven member may outrun the drivingmember in the direction ofthe torque and thus freewheeling at high speedis possible for the same reasons as were set forth in the discussion ofFig. 10. Fig, 12, therefore, shows the high-speed, single-look set-up.

Fig. 13 shows the high-speed double-lock setup. The lugs 41 are entirelywithin the slots of the hub 43 and the hub 43 is free to move in bothdirections. No freewheeling is possible in this set-up.

In shifting from the neutral to either intermediate position, asindicated in Figs. 10 and 12, the operator is liable to move the lever53 either too far or not far enough and thus fail to position the lugsproperly within the hub slots. To insure that these lugs will be movedto and stopped. at

1 .their proper positions, I have provided the stop mechanism which isshown in Figs. 1, 6, '7 and 8. The shifting member is provided withapair of upstanding lugs 56 and 56 in the upper ends of which arevertical slots 51 through which extends a rod or shaft 58. The centralpart of this rod has a diameter which is but slightly less than thewidth of the slots. The ends, however, are enlarged at 59 and arejournaled in the casing extension 20 The inner ends of these enlargedends form stops for arresting the move ments of the shifting collar 48at the ends of its strokes when the lugs 41 are brought into thepositions indicated in Figs. 9 and 13. Each of these end portions isprovided with a pair of diametrically-disposed lugs 60 which extendparallel with the shaft 58 and have a thickness substantially equal tothe diameter of the shaft. When the shaft is in the position shown inFigs.

6 and '7, the lugs 56 and 56 may be shifted to their full extent to bearrested by contact with the enlarged ends 59 of the shaft, since thelugs 60 may then enter the slots 51 without interference with the lugs56 or 56 as the case may be. When, however, the shaft-58 is rotated, asindicated in Fig. 8, theselugs extend more or less transversely of theslotsso as to be engaged by the lugs 56 or 51 and thus arrest themovement of the shifting collar when the lugs 47 are in theirintermediate positions, as indicated in Figs.

and 12. It will be noted that the shaft 58, with its enlarged ends andstop lugs 60, forms not only a means for controlling the extents ofmovement of the shifting collar, but is also a guide which holds themember 5| in its upright position, as in Fig. 1. Any suitable hand orfootoperated means may be employed for turning the shaft 58. In theoperation of modern automotive vehicles, the driver releases the clutchbefore shifting the'gears and he does this by depressing theclutch'pedal. It would be convenient and in accordance with theabove-stated practice, to rock theshafit 58 by means connected with theclutch pedal, and sucha-means is indicated in Figs. 1 and 6, wherein thepedal is shown witha'bell-crank 64 which has an arm 65 adapted forengagement with a pin 66 on the shaft 58. As indicated in Fig. 6, thispin is preferably forked to receive the arm 65 in order that the shaftbe returned to the position of Fig. '6 when the pedal is released. Thepin 66 is rigidly attached to the shaft 58 and the shaft must turn asthe pin is moved by the arm 65. Figs. 7 and 8 show, partly in dottedlines, the forked construction of the pin 66, and this is shown in Fig.6 as well. The shaft 58 could be returned to its normal position 'ofFig. 7 by various kinds of means; but the spring which sets the clutch(not shown) is admirably adapted for that purpose. When, therefore, thepedal 6| is released and the clutch spring causes the clutch to engage,the shaft 58 is automatically restored to its normal position, as inFig. 7.

In Fig. 14 I have shown a modified structure of the means for clutchingthe driven member to the gears 21 or -32. Instead of using rollers, suchas 29 or 33, I employ non-cylindrical elements "6'! which are insertedbetween the fingers 4| a of the cages. The outer surfaces of theseelements are rounded to fit against the surface 28 or 28 of therespective gears, while the inner surfaces are V-shaped, as shown, andare projected into the V-shaped grooves 40 of the driven member. When intheir central or neutral positions, the apices of the elements extendinto the apices of the grooves, as in Fig. 14, while the outer surfacescontact lightly with the surface 28 or 28 Instead of having single linesof contact, as do the rollers 29 and 33, the elements 67 bear against amuch more extended area and produce sufficient friction to shift thecages.' Consequently, in this structure no friction shoes, such as 44,are required, and the outer surfaces of the fingers 4| are continuouscircumferentially, as shown. When either of the cages is released forshifting, as has been described, the elements 61 are shifted with itabout the member 24. The inclined walls of the grooves 40, acting ascams, press the elements more lightly against the surface 28 or 28 ofthe gears until they jam and clutch the member 24 to the gears.

Fig. is a fragmental view of a modified form of the hubs for the cages,the hubs being designated 43 and 43 and the slots 54 and 54 When thehubs are in their normal or neutral positions, the slots are inalinementy Projecting inwardly from what is shown as the upper side ofthe slots are lugs 68 and 68, and extending outwardly from the lowerside thereof are notches or widened portions 69 and 69 Between the lugsand the respective outer ends of the slots are widened portions of theslots, designated 'lll and 70. Slidable within the said slots are a pairof lugs 41* and 4! which project from a body member having a slot 49which corresponds to the slot 49 of Fig. 2. Projecting from the lug 41is a widened portion H which is adapted to enter. the part 69 of theslot 54', and a similar widened portion 12 projects from the lug 4'! andis adapted to enter the widened portion 59 of the slot 54. Although thedriven shaft 24 does not appear in Fig. 15,.it is to be understood thatthe lugs 41 and 4'! project into the slot 46 of the shaft as do the lugs41 of Fig. 2.

When the parts are in the positions shown in Fig. 15, the cages arelocked to the shaft and the clutch elements 29, 33 or 6'! are in theirnonoperative position. When the lugs are shifted to the left in Fig. 15until the lug 41 clears the projection 68 the cage hub 43 can shift tobring the said lug into the widened portion it But the said hub cannotshift in the opposite direction because the part ll of the lug is stillin engagement with the lower edge of the slot 54 When, however, the lug'i is moved the next step, the part II thereon is brought into positionto enter the notch 69 and the cage hub 43 can then shift in bothdirections. Thus may the hub be held in neutral, be locked in onedirection only, or be freed to shift in either direction for thepurposes described in connection with Figs. 9 to 13. While the lug M isthus controlling the cage hub 13 the lug 41 is holding the cage hub 43in its neutral position. To control the latter hub, the lugs are movedto the right, during which movements the hub 43* is held in neutral. Itwill be noted that whereas, in the structure of Fig. 2, one of the cagehubs is controlled by moving the lug in the direction away from thathub, in the structure of Fig. '15 the hub is controlled by moving itslug 4'5 or 4? toward it. In other words, the lugs are shifted indifferent directions in the two structures. In both cases, the clutchelements are maintained in their neutral positions, are caused to clutchin one direction only or in both directions all by the movements of asingle operating lever or other suitable device.

I claim as my invention:

1. In clutch means for connecting two relatively rotatable members, saidmembers being axially alined, a driven shaft extending axially withinsaid members, both of said members having axial bores about the shaftand larger than the shaft whereby a circumferential space is leftbetween the shaft and the inner walls of said bores, the shaft beingprovided with grooves at those parts which are surrounded by saidspaces, said grooves having an inclined side Wall serving as a cam,clutch elements within said spaces and grooves, a pair of cagessurrounding the driven shaft between the said members, means projectingfrom one of the cages into the space of one member and engaging theclutch elements in said space to move said elements, similar meansprojecting from the other cage into the space within the other memberand engaging the clutch elements therein, the adjacent ends of the cageseach being provided with a slot and the driven shaft also having a slotadapted to register with the slots in the cages, a collar surroundingthe said cages, a lug projecting from said collar through one or both ofsaid cages and into the slot in the said shaft, means for shifting thesaid collar longitudinally of the shaft to cause the lug thereon toengage one or both the collars within the slots therein, whereby eitheror both of said collars becomes locked to the shaft or is freed from theshaft and the freed collar may turn on the shaft to move its clutchelements up an inclined side of the groove in the shaft and intoclutching relation with the respective gear.

2. Power-transmission mechanism as set forth in claim 1 in which themeans projecting from the cages into the spaces within the memberscomprises spaced fingers and in which the clutch driven shaft, thus tocause the clutch elements of the latter cage to clutch the said shaft tothe respective member.

4. Power transmission mechanism as set forth in claim 1 in which themeans projecting from the cages into the spaces within the memberscomprises spaced fingers, each of which is provided with a shoe having afriction surface fitting against the wall of the bore of the respectivemember to produce a drag between the cage and said wall to cause thefreed cage to move rotatably on the driven shaft, thus to cause theclutch elements of the latter cage to clutch the said shaft to therespective member.

5. In power-transmission mechanism comprising two spaced and coaxiallydisposed driving gears each of which is provided with an interiorannular clutch surface, and having means for rotating said gears atdifferent speeds, a driven shaft coaxial with the said gears and withinthe said clutch surfaces thereof, being spaced from said surfaces, saidshaft being provided with V- shaped grooves on its parts which arewithin the clutch surfaces of said gears, a pair of independentlymovable cages mounted upon the shaft between the said gears, one of saidcages projecting into the space within the clutch surface of one gearand the other cage projecting into the space within the clutch surfaceof the other gear, clutching elements in the projecting parts of saidcages within the said spaces and within the respective V-shaped groovesin the driven shaft, each of said cages having a hub part extendingtoward the other cage and each of said hub parts having a slot in itsend, said slots being in alinement and opening toward each other andbeing widened at their open ends and said shaft having a slot therein inregister with the narrow parts of the hub slots when the clutchingelements are centered in the V-shaped grooves of the shaft, a lugmounted to reciprocate in said hub slots and in the slot in the shaft,and means for reciprocating said lug toward and from the said gears, forthe purposes specified.

6. Power-transmission mechanism as set forth in claim 5 in which theclutching elements are rollers having their axes parallel with the axisof the shaft.

'7. Power-transmission mechanism as set forth in claim 5 in which thelug which reciprocates in the hub and shaft slots has a thickness whichis substantially equal to the width of the narrow parts of the hub slotsand a width which is greater than the widened parts of said slots sothat the hubs are held non-rotatable on the shaft while the lug is in acentral position and is within the narrow parts of the slots of bothhubs, but either hub is permitted a slight turning movement on the shaftwhen the lug is shifted from its cen tral position and is out of thenarrow part of the movable hub.

8. Power-transmission mechanism as set forth in claim 5 in which the lugwhich reciprocates in the hub and shaft slots extends across the widenedpart of both of the hub slots and into the narrow parts of said slotswhen the lug is in iii) its central position so that both of said hubsare held non-rotatable on the shaft and all the clutching elements aremaintained out of clutching engagement with the inclined sides of theV-shaped grooves, in which, when said lug is moved to an intermediateposition, it is removed from the narrow part of one of the hubs and thathub is free to rotate slightly on the shaft in one direction only tocause its clutching elements to engage with one inclined side of thecorresponding V-shaped grooves to clutch the shaft to the respectivegear, the lug then ,pro- J'ecting into the narrow part of the slot ofthe other hub and holding it against rotation on the shaft, in whichintermediate position the shaft is driven with the'gear but may overrunthe latter, and in which, when the lug is moved to its 'third position,it is freed from the narrow part of the slot of the previously rotatablehub and the latter is then free to rotate in both directions on the saidshaft to cause its clutching elements to engage with either of theinclined sides of the V-shaped grooves, thus to prevent overrunning ofthe shaft.

9. Power-transmission mechanism comprising two spaced and coaxiallydisposed driving gears each of which is provided with an interiorannular clutch surface, means for rotating said gears at differentspeeds, a driven shaft coaxial with said gears and within the saidclutch surfaces thereof, being spaced from said surfaces, said shaftbeing provided with V-shaped grooves on its parts which are within theclutch surfaces of said gears, a pair of independently movable cagesmounted upon the shaft between the said gears, one of said cagesprojecting into the space within the clutch surface of one gear and theother cage projecting into the space within the clutch surface of theother gear, clutching elements in the projecting parts of said cageswithin the'said spaces and within the respective V-shaped grooves in thedrivenshaft, each of said cages having a hub part extending toward theother cage and each of said hub parts having a slot in its end, saidslots being in alinement and opening toward each other and being widenedat their open ends andsaid shaft having a slot therein in register withthe narrow parts of the hub slots when the clutching elements arecentered in the V-shaped grooves of the shaft, a lug mounted toreciprocate in said hub and shaft slots, means for reciprocating saidlug toward and from the said gears, said lug when in its central andneutral position extending across the widened parts of both hub slotsand into the narrow parts of said slots and holding both hubs againstrotation on the said shaft and maintaining all the clutching elementsout of clutching engagement with the shaft, the said lug when in itsintermediate position remaining in the narrow part of the slot in thehub toward which it is moved and extending into the widened part only ofthe slot in the other hub whereby the latter hub is free to turnslightly on the shaft in one direction only to cause its clutchingelements to move up one inclined side of the V-shaped grooves toestablish an overrunning clutching engagement between the shaft and therespective driving gear, and

the said lug, when in its third position being free from the said otherhub so that the latter may turn slightly in either direction on theshaft to establish clutching engagement between the respective gear andeither side of the V-shaped grooves, thereby preventingroverrunning ofthe shaft with respect to the gear.

10. Power-transmission mechanism as set'forth in claim 9 having manuallycontrolled means for arresting the said lug in its intermediatepositions.

11. Power-transmission mechanism as set forth in claim 9 embodied in anautomotive vehicle having a clutch pedal, means for arresting the saidlug in' its intermediate positions, and connections between said lattermeans and the said clutch pedal.

ARNOLD H. JESSEN.

